title: Assessing pathogenicity of Gallibacterium anatis in a natural infection model: the respiratory and reproductive tracts of chickens are targets for bacterial colonization.
abstract: Two separate bird trials were performed to establish a reliable route of infection for Gallibacterium anatis in chickens, comparing intranasal (i.n.) and intravenous (i.v.) applications. Additionally, three mutually divergent isolates from three geographical locations, as shown by MALDI-TOF-MS and partial rpoB gene sequence analysis, were compared. In the first trial, birds were infected with one of the selected isolates by the i.v. or i.n. route. Subsequently, birds were killed 3, 12 and 24 h post infection following i.v. infection while at 3, 7 and 10 days post infection (dpi) in the case of i.n. infection along with birds of the control group. As a result, i.n. infection showed prominent and consistent bacterial tissue distribution in different organs persisting until 10 dpi, which was a striking contrast to the i.v. infection route. Likewise, histopathology revealed mild to severe tracheal lesions following i.n. infection. The second trial was set up to confirm both the achieved results and the robustness of i.n. infection but with an extended observation period, until 28 dpi In agreement with the preceding trial, identical results for bacteriological and histopathological examinations were obtained with persistency of bacteria until 28 dpi Comparing the three different isolates from Mexico, China and Austria, the Mexican isolate showed a somewhat higher pathogenicity than the other strains. Consequently, pathogenesis of G. anatis strains was studied in chickens elucidating i.n. infection as the most reliable route characterized by a long-lasting bacteraemia, targeting the respiratory and reproductive tract.
authors.affiliation: a Clinic for Avian, Reptile and Fish Medicine, Department for Farm Animals and Veterinary Public Health , University of Veterinary Medicine , Vienna , Austria.
authors.forename: Surya
authors.initials: S
authors.lastname: Paudel
authors.forename: Merima
authors.initials: M
authors.lastname: Alispahic
authors.forename: Dieter
authors.initials: D
authors.lastname: Liebhart
authors.forename: Michael
authors.initials: M
authors.lastname: Hess
authors.forename: Claudia
authors.initials: C
authors.lastname: Hess
mesh_terms: D000281:Administration, Intranasal; D061605:Administration, Intravenous; D000818:Animals; D001317:Austria; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002645:Chickens; D002681:China; D017931:DNA Primers / Q000235:genetics; D008800:Mexico; D008969:Molecular Sequence Data; D015661:Pasteurellaceae / Q000235:genetics / Q000472:pathogenicity*; D016871:Pasteurellaceae Infections / Q000662:veterinary*; D011201:Poultry Diseases / Q000382:microbiology*; D060737:Reproductive Tract Infections / Q000662:veterinary*; D012141:Respiratory Tract Infections / Q000662:veterinary*; D017422:Sequence Analysis, DNA / Q000662:veterinary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000662:veterinary; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers